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2011 Subaru Outback 2.5liter vs 3.6 liter engine

I have decided to purchase a 2011 Subaru Outback. My dilemma is choosing between the 2 engines offered. I live in a hilly/mountainous region and have heard that the mpg can actually be better with the larger motor with less “wear and tear” and longer engine life. Any truth to this? Can you direct me to references regarding this topic? Thanks. Rick D. Salem Oregon

I would opt for the larger engine, simply because it is a more pleasing vehicle to drive, due to the “effortless” acceleration and the lower level of engine noise. As to gas mileage, the 2.5 liter engine will definitely get better gas mileage than the 3.6, mainly because it is linked to either a Continuously Variable Transmission or a 6-speed manual trans. The 3.6 liter engine uses a “conventional” 5-speed automatic trans.

In addition to the power factor, the 3.6 liter six-cylinder engine utilizes a timing chain, rather than the timing belt that the 2.5 liter four-cylinder engine uses. Ergo–less maintenance. Additionally, while head gasket problems seem to be largely resolved with the 2.5 liter engine, there is still the lurking possibility of that problem. By contrast, the 3.6 liter six has no record of head gasket failures.

As to longer engine life, that is a difficult one to answer. I suppose that if someone is intent on lots of hard acceleration, the six may last longer than the four, simply because it never has to work as hard to produce the same speed, but for most people the engines would probably have a similar life span.

Thank you. Any idea why Subaru doesn’t use continuous variable transmission in the 6 cylinder or offer the same motor with the turbo feature they only offer in the 2.5 liter Forester?

As I understand it, their CVT cannot currently stand up to the added torque of the 6-cylinder.
As to whether the CVT is offered with the turbo 4-cylinder, that combination might be offered on the Legacy sedan in the US, but is not offered on the Outback in the US.

The offerings are likely to be somewhat different outside of North America.
For instance, in Europe the Outback is offered with a common-rail, direct injection Diesel engine, coupled with a manual transmission.

Since you live in Oregon, I would say that you have conditions that are similar, but maybe not as severe are the driving conditions here in Denver, CO.

Just about every Subaru here in the Denver area is sporting the 4 cylinder engine, and is doing just fine with the mountains. only every now and again do you see a Subaru with the 6 cylinder engine, but typically not for very long, as it thrusts away from view.

Since there are complaints very frequently about the 4 cylinder engine having head gasket failures, but not from the 6 cylinder cars, you could almost surmise from that the 6 cylinder engines have a greater initial lifespan. Most of the 4 cylinder cars seems to need to have the head gaskets replaced somewhere between 100k and 150k miles.

As to better fuel economy due to the bigger engine, that would really only happen at highway speeds, while climbing a hill, where the 4 cylinder car needs to downshift a time or two, and run at full throttle, where as the 6 cylinder engine doesn’t need to do that because of the extra power. That’s the only time.

Easy way to find out which one is the right engine for you is to call up your Subaru dealer, and tell them you want to test drive both cars on your normal route, filling each one up before and after the loop. Then you can see which one used more gas under your normal driving conditions. I’m sure a dealer that wants to make a sale will be more than willing to let you do this.


Don’t believe the hype about longer engine life.

My inlaws(4 Subaru) all have achieved 225k-275k with their 4 cylinder (2.5L) Subaru engines with any serious repairs. The 225k had failed AC and only one that blew its head gasket and was traded in for another.

The MPG will likely be better with the 2.5L by a good margin.

However the 2.5L non turbo is nothing exciting to drive. I would never buy it. Thankfully my wife 8 months pregnant picked up a 2005 Legacy gt(turbo 2.5L) wagon 5 speed manual that we still enjoy driving to this day now with 90k miles.

My only tip is get a Subaru Chase Mastercard if you pay your balances off. It kicks back 3% that earns you up to $500/year for Subaru delaer service. I have yet to pay out of pocket for maintenance/service work to our 2005 Legacy with 90k except oil changes and two sets of tires. Servicing is more expensive than average car on Subaru.

Longer-lived? no
Better mpg? no
But more fun, better acceleration, smoother, effortless? Absolutely.

Take extended test drives in each, see which you like.

I wouldn’t touch a cvt with a ten foot pole. I drove one and I hated it. If this is the future I’ll go back to a stick shift.

Not all CVT’s are created equal. I don’t think a broad statement can be applied to them all. It is application specific.

A four cylinder will last just as long as a 6 or 8 if driving and maintenance habits are equal.

The fuel mileage part can vary but it is often true that a larger engine or one with more cylinders may get better mileage than a smaller one or one with fewer cylinders and often fuel mileage is about the same no matter the size or number of cylinders.

I’d go for the bigger engine if it were my decision. My Lincoln Mark has a near 300 HP V-8 and the fuel economy on that is the same or better than my youngest son’s Toyota Camry 4 cyl., my oldest son’s Dodge Caliber 4 cyl., or my daughter’s 4.0 V-6 Mustang.

WE are considering to purchase a new 2011 subaru outback; please share your experiences if you own one…we will buy 4 cyl with auto tranny, thanks

I have a 2011 Outback Limited, with the 3.6R six cylinder engine.
While the engine and the transmission are different, the rest of the car is essentially identical to the the 4 cylinder model that you are planning on buying.

Incidentally, the transmission choices for the 4 cylinder engine are a 6-speed manual or a Continuously Variable (CVT) transmission. A conventional automatic is not available with the 4 cylinder model.

While I advise purchase of the 6-cylinder model for its much lower noise level and (obviously) much higher power output, many drivers are satisfied with the power output of the 4 cylinder models. Of course, you will get better gas mileage with the 4 cylinder, but that powerful six is not exactly a gas hog either. My typical around-town gas mileage is 22-23 mpg, and on a long highway trip I can easily get 27 mpg out of the six.

Overall, I am extremely impressed with the vehicle. It is extremely quiet and smooth-riding, and powerful, yet economical. It has an incredible amount of interior room, given the outside dimensions. This is my 3rd Outback, and it clearly has the highest build quality of all 3.

No matter which engine you choose, I suggest that you opt for the Limited model.
I say this because of several factors, but chiefly the air conditioning. One of the few complaints of owners of base and premium models is that the manual A/C on these models cycles to a warmer setting after 15 minutes of operation. By contrast, the automatic climate control on the Limited model produces bone-chilling A/C from start-up to the end of the day. If you live in a warm climate, you will really appreciate the A/C of the Limited model.

After looking at some of the specs between the 4 and 6 cylinder I wouldn’t be too concerned which one will be better on mileage since they both are pretty close together. I think the price difference in the engines is more of a concern than the MPG rating. If you can afford the model with larger engine I would go with it myself but you should decide what is best for you.

Good tip about the A/C unit VDCdriver. I keep my vehicles a long time so going with the top end models is a good way to go I think also.

Is the 4 in the Outback the new one with timing chains instead of belts, like it is in the Forester? I’d want that.

The new-design 4 cylinder engine (utilizing a timing chain) that was recently introduced for the Forester is definitely not being used on the 2012 Outback. It is not even clear at this point if that engine will be used on the Outback for 2013.

Cougar and I agree on buying the top-end model.
When you amortize the extra cost of the luxury model over many years of ownership, it actually amounts to mere pennies per day to enjoy better seats, better A/C, more sound-proofing, and other nice bells and whistles that make you more comfortable behind the wheel.

The 2012 will have a timing chain and the DOHC design currently used in the Forester, or so I was told when I test drove the 2011. Check out the subaru outback forum to see what people are saying about their Outbacks, if it matters to you. I agree - take an extended test drive to see which engine works the best for you. I find it is hard to tell from what people say. In the meantime, I’m keeping my '96…

“The 2012 will have a timing chain and the DOHC design currently used in the Forester, or so I was told when I test drove the 2011.”

Well, perhaps that salesperson is correct.
However, I have found over the years that the vast majority of car salespeople are woefully misinformed about the vehicles that they are selling. After doing my own personal due diligence prior to visiting showrooms, I have almost always found that I knew more about the vehicles in the showroom than the sales folk did.

My favorite salesman story was related by my brother and SIL.
Back in the late '80s-early '90s, my brother asked a salesman to explain the function of a button on the dashboard of a particular vehicle that was marked “Traction Control”.
First, you have to be aware that my brother was well aware of the function of that button, and he was trying to assess whether that salesman had sufficient active brain cells in order to make it worthwhile to spend any time with him.

The salesman’s reply was, “Oh–when you push that button, it makes the car heavier”!
While attempting to stifle their laughter, my brother replied, “I’m REALLY impressed that this car can defy the laws of physics by the mere push of a button”.

While the salesman scratched his head in an attempt to deciper what my brother had said, my brother and SIL left the showroom in search of intelligent life elsewhere. As I said, the salesman to whom you spoke might be correct, or he could be totally out in left field–like so many other car sales folk.